Claimed OU circuit of Rosemary Ainslie

[PaulLowrance]

BTW, don't know if anyone's mentioned this, but there are inexpensive DC amp clamp meters. It does not touch the wires, and will show DC current. Not sure how much inductance they have, but probably not that much.

Paul

[poynt99]

I'm waiting to hear back from my contact at Tektronix as well.

I'm confident he will state that the Tektronix article does apply to the circuit we are dealing with here, and that everything I have stated is valid.

.99 

[Harvey]

The formula is not my own. These are screen shots taken from:

http://www.captain.at/electronics/coils/


Using 48 turns and 130mm length results in 16.08uH as shown.

.99

I think I see a problem. That formula is for inches, not millimeters. Is there a check box somewhere that converts it for you? I haven't checked your results yet, but as I recall they are very close to what I derived also.

[Harvey]

Unsubstantiated statements. Harvey's post adds no substantiation to this whatsoever.
Says nothing about the issue at hand, and is an incorrect statement. Specifications are different than procedures. Using a single-ended probe even correctly has it's limitations and Tektronix will not argue with this fact. The limits of this measurement technique have been exceeded for this application, and again Tektronix would not argue with this.

.99

Ok, now you have piqued my curiosity here...what limits have been exceeded?

[Harvey]

Days ago I offered another testing method. It's not my initial preference, and probably not .99 preference since the standard more conventional method is to measure the DC current through the battery shunt, but this method would also work, and it should make everyone happy,


This method does *not* require a scope, or the battery shunt resistor, or any shunt resistor. The ambient room temperature should be between 60F & 90F. Pick a room temperature that you can maintain relatively stable, which we will refer to as RT (short for room temperature).


* Place a small thermistor on the load, and one on the mosfet.

* Connect an appropriate thermistor circuit (a simple current current source & an op-amp circuit will due) to each thermistor to monitor the temperature.

* This testing method uses a small rechargeable battery. Never load this battery over 1/10th of its maximum load. *Slowly* recharge the battery. For 12V vehicle battery, 12.65V is good. For 6V vehicle battery, 6.3V is good. The room temperature should *not* change more than +/- a few degrees of RT during the battery recharging period.

* Very important: Let the battery rest unused for at least 24 hours.

* Bring the room temperature to RT (+/- a few degrees at most), and maintain that temperature for at least 1 hour, then take battery voltage measurement, which we will refer to as T1.

* Run the Ainslie circuit. Take a quick battery voltage measurement every so often. Never leave the voltage meter on the battery while the Ainslie circuit is running, as Ainslie might accuse this as absorbing the energy spikes or whatever. Also, try to keep the *battery* temperature near RT, +/- 8 degrees. Measure the mosfet & load temperature. Write this down, as well as the time (including the minutes) every so often, as this will be used in a control experiment to calculate the total energy. The mosfet & load temperature should remain relatively constant. Also log the room temperature as well.

* Stop the Ainslie circuit when the battery voltage has dropped by 1.6%.

* Let the battery rest for one day.

* Slowly change the room temperature to T1, and try to maintain the temperature for *at least* 1 hour.

* When you have maintained the room temperature close to T1 (+/- a few degrees at most) for at least one hour, then take a voltage measurement, and we will refer to this as V2.

*  ***Slowly*** recharge the battery to the V1. Do not exceed 0.1 amps!

* Now for the battery control experiment. Disconnect the battery and let it rest for at least 12 hours, preferably 24 hours.

* Connect a load to the battery. The load resistance depends on your load power rating. Do *not* exceed 1/10th the power rating!! If the load is rated at 10 watts, then do not exceed 1 watt. Also, you should be able to hold your fingers on any part of the resistor without any discomfort from heat. If it's too hot to tightly hold your fingers on the load, then the load resistance could change by an appreciable amount. At 1 watt with a 12V battery the load resistance would be 12V^2 / 1W = 144 ohms. So the resistance must be at least 144 ohms, you can use a resistor with more resistance. Maintain the room temperature at RT, +/- a few degrees. Also, very important, take a voltage measurement every so often and write this down along with the time (including the minutes). This data will be used to create a voltage graph, which will be used to calculate the total energy.

* When the battery voltage is dropped to V2, then remove the load. Then *quickly* take an ohm meter to measure the load resistance. Write down the resistance.

* Now for the mosfet & load control experiment. Calculate the average mosfet temperature during the Ainslie experiment, which we'll refer to as Tmosfet. Calculate the average load temperature during the Ainslie experiment, which we'll refer to as Tload.

* Connect the mosfet drain & source to a battery, and connect a variable voltage source to the gate. Slowly increase the gate voltage until the mosfet temperature stabilizes to Tmosfet. Measure & write down the voltage across the mosfet drain & source.

* Connect a variable voltage source to the load. Slowly increase the voltage until the load temperature stabilizes to Tload. Measure & write down the voltage across the load.
 
 
That's it! Unless I forgot something, that's enough data to tell if the Ainslie circuit is > cop 1.


Paul

Paul, I will admit here that this is the first post from you that I have carefully read so as to ascertain your approach. There are several things in your approach that need to be addressed.

1. Battery drain curve calibration for:
a) Continuous DC
b) Pulsed DC
c) Oscillatory AC
d) Aperiodic Oscillatory AC

2. Thermocouple TC curve calibration reference

3. Ambient dissipation characteristics (thermal resistance) for:
a) Load Resistor
b) Power Transistor
c) Thermal Paste or Sil-Pad
d) Power Transistor Heat Sink

4. Allowed error margins e.g. 8°F on Battery case? Or is that a fluid measurement of the acid?
5. Is there any need to monitor the ambient during your test or just as long as it is within "a few degrees"?


As an aside here, and this is a point which Rosemary as voiced on numerous occasions, why hasn't anyone mentioned the use of a hydrometer for determining the actual charge associated with the battery?